Method and mechanism for continuously forming liquid-impervious plugs in extraction units



Dec. 19, 1939. BQNQTTQ 2,184,248

METHOD AND MECHANISM FOR CONTINUOUSLY FORMING LIQUID-IMPERVIOUS PLUGS IN EXTRACTION UNITS Filed Aug. 6, 1936 5 Sheets-Sheet 1 9 5 v o- T ono 72 H "3 EXT/ffiCT/U/I/ MISC'EZM UNIT 0/5T/LLER 7 Z Z INVENTOR.

BY 4 2E v ATTORNEY.

Dec. 19, 1939. BONQTTO 2,184,248

METHOD AND MECHANISM FOR CONTINUOUSLY FORMING LIQUID-IMPERVIOUS PLUGS IN EXTRACTION UNITS Filed Aug. 6, 1936 3 Sheets-Sheet 2 INVENTOR. WA 51mm ATTORNEY.

Dec. 19, 1939.

M. BONOTTO METHOD AND MECHANISM FOR CONTINUOUSLY FORMING LIQUID-IMPERVIOUS PLUGS IN EXTRACTION UNITS Filed Aug. 6, 1936 3 Sheets-Sheet 3 7 z INVENTOR.

Patented Dec. 19, 1939 UNITED STATES PATENT OFFICE Michele Bonotto, Evansville, Ind., assignor to Extractol Process, Ltd., Wilmington, Del a corporation of Delaware Application August 6, 1936, Serial No. 94,582

7 Claims.

This invention relates to improvements in method and mechanism for continuously forming liquid-impervious plugs in extraction units.

It is desirable in extraction units of the continuous counter-current type to form at the material-discharge end of the unit a liquid impermeable plug of material, and the formation of such a plug is particularly desirable in extraction units of the type specified in my former 10 application Serial No. 48,646, filed on the 7th day of November, 1935, for Process and apparatus for extraction of oils, fats, and other soluble constituents from materials containing the same.

By the use of my present invention, I am enabled to provide at the material-discharge end of an extraction unit a plug composed of the oilbearing material employed in the extraction process, which will have suificient density to be impervious to the liquid solvent employed in the process and will form a tight joint with the packing conduit, while permitting continuous discharge of material from such conduit.

It has been found in practice that the use at the discharge end of an extraction unit of a conventional material-discharge or conveyor screw will not produce a sufficient packing against a pressure-exerting valve at the dis charge end of a conduit to enable the formation of an impervious plug and that such a screw cannot be made to provide suflicient pressure on the plug-forming material to produce an impervious plug of such material. Efiorts have also been made to use a conveyor screw and conduit with tapering ends but it has been found that such mechanism does not produce satisfactory results in the packing of an impervious plug. In accordance with my present invention I utilize a mechanism which will cause anincremental packing within a passage of increased area of the said material as it is discharged through the discharge outlet of the unit proper and I preferably provide a cylindrical packing conduit for the material of larger area or diameter than the discharge outlet, and incrementally pack the material in this passage independently of the packing caused by the conveyor screw within the unit which conveys the material to said packing space.

In the preferred form of my inventlon I provide a trough at the bottom of a unit for which it is desired to provide a material-plug, mount a conventional rotatable discharge screw therein and use this screw to convey the material to an outlet-opening. I then provide a plug-forming 5m conduit of larger diameter than the outlet or discharge aperture, and mount in said enlarged conduit a spiral member or packing screw of larger diameter than the conveyor screw first mentioned. This larger packing screw thus receives the output of the smaller conventional- 5 screw and is enabled to pack the same into the enlarged conduit in an incremental manner. The packing conduit is provided, at its entrance end, with a screwenclosing section for said enlarged screw, an intermediate outer packing 10 space and a closed or partially closed outer end at which pressure is applied by a pressure-exerting member or a spring-pressed conical valve.

Another feature of my invention is the provision of a spiral bore in said packing conduit 15 adapted to cooperate with said packing spiral or screw to move the material spirally during the packing of material therein and I preferably provide, at the screw-enclosing section a series of spiral ribs on the inner wall or surface 20 of the packing conduit.

' Another feature of my invention is the provision of means for preventing the liquid solvent from following or forming a channel surrounding the periphery of the screw actuating shaft 5 which preferably extends through said plug in the packing conduit, and for this purpose I provide a shaft having a periphery tapering gradually from its outer end portion to its connection with the packing screw and thus gradually 30 widening in diameter outwardly from the innerend of the plug-forming section of the conduit toward the outer-end thereof.

With these and other objects in view, the invention comprises the combination of members 35 and arrangement of parts so combined as to coact and co-operate with each other in the performance of the functions and the accomplishment of the results herein contemplated, and comprises in one of its adaptations the species 40 or preferred form illustrated in the accompanying drawings, in which-- Fig. 1 is a vertical section of an extraction unit for use with a solvent of low specific gravity and with my improved plug-forming mecha- 45 nism embodied therein;

Fig. 2 is an enlarged fragmentary vertical section of the bottom part of the unit and plugforming mechanism;

Fig. 3 is a fragmentary cross-section on the 50 line 33 of Fig. 2, looking in the direction of the arrows;

Fig. 4 is a fragmentary cross-section on the line 4-4 of Fig. 2, looking in the direction of the arrows; to

Fig. 5 is a fragmentary longitudinal section on the line 5-5 of Fig. 2, looking in the direction of the arrows;

Fig. 6 is a central vertical section of an extraction unit for use with a solvent of high specific gravity and having my plug embodied therein;

Fig. 7 is a section on the line 1-1 of Fig. 6 looking in the direction of the arrows.

Fig. 8 is a section on the line 8-8 of Fig. 6 looking in the direction of the arrows.

Referring now to these drawings and particularly to Figs. 1 to 5, I indicates an extraction unit or tank, the extraction section I' of which is preferably divided into a series of intermingling zones a, b, etc., preferably divided by a series of discs 3, having vertically non-registering and radially-disposed apertures 3'. The

discs 3 are mounted on a central shaft 4 and preferably revolve in a horizontal plane without causing the solid material to revolve therewith. I preferably provide within the tank I scraper arms 5 which are suitably supported within the tank to provide a positive stop against the revolving of the material with the movement of the discs. This mechanism more particularly forms the subject-matter of my earlier application Serial No. 48,646, filed November 7, 1935, and is here illustrated to show one form of an extraction unit in which solid material tobe extracted and a solvent are caused to be moved continuously in counter-current through the extraction section and the solid material is formed into an impervious plug at the discharge end thereof. In the unit illustrated, after the material passes through the zones a, b, etc., it is caused to pass through a bottom expansion chamber 8 which is preferably, as illustrated particularly in Figs. 2 and 4, provided with inclined sides 8', it merging into a trough or casing 8 within which is mounted a horizontally-disposed perforated conveyor-screw IIl' mounted on a horizontal shaft I I' which may be rotated from any suitable source of power and, as shown, is rotated by bevel pinions II, II the latter of which is connected to a vertical shaft S extending to any suitable source of power, not shown.

In the case of a unit adapted for use of a light solvent, such as gasoline, it is provided at its top with a feed-hopper I having a feeder I and is preferably at its lower end, provided with the aforesaid expansion chamber 8 having the aforesaid inclined sides 8', 8* merging with the trough or casing 8 within which is mounted the conveyor screw Ill rotated as hereinabove specified.

In the unit embodiment illustrated, the shaft 4 and discs 3 are rotated and a charge of solid oil-bearing material is fed from one intermingling zone into successive intermingling zones from thetop of the tank to the bottom or vice versa, in accordance with the type of solvent employed, and in each zone extraction is carried on until the material from which the oil has been extracted by the solvent reaches the compartment 8.

In the said preferred embodiment of my invention illustrated, the revolving shaft 4 terminates within the expansion chamber 8 and is supported at opposite ends in bearings 9, 9'.

The horizontally-disposed and perforated conveyor screw I0 is rotated in its trough or casing independently of the: shaft 4 and conveys or moves solid material, which passes to the bottom by gravity, through an opening I in the tank I and by my present invention I form this material from which the oil has been extracted into a liquid-impervious plug and with this end in view, the opening I communicates with a packing conduit I2 of an incrementallypacked plug-forming mechanism. In order to provide for such incremental packing, the communicating opening I is of a transverse area smaller than the transverse area of the conduit I2. The opening I is preferably circular and the conduit I2 is preferably cylindrical. The perforated screw I0 thus continuously feeds solid material through the opening I which is the entrance opening to the conduit I2, and in view of the difference in area 01' the conduit and opening the material fed through the opening will not, assuming that it be continuously moved, fill the said conduit at the space adjacent to the entrance opening but will, on the contrary, leave a free space I2 near said entrance opening so as to enable an incremental packing of such material within the said conduit, and the material thus being fed through the entrance opening I will, in accordance with this invention, be incrementally packed continuously within the said conduit I2 by suitable mechanism.

In the preferred form of mechanism illustrated, I provide, within the conduit I2, a relatively short perforated screw I2 revolving within one end of the conduit and having a diameter slightly smaller than the internal diameter of the conduit I2 but considerably larger than the opening I and also larger than the conveyor screw III, so that it will have a capacity, when moving at the same rate of speed, which will be greater than said screw Ill and greater than the quantity of material being passed through said opening I. This large perforated screw I2 is mounted to project and revolve within the conduit for a relatively short distance and is, as shown, on a shaft portion II which is a continuation of the shaft II, being, as shown, formed integrally therewith and ex tending within the conduit I2. In my preferred formof mechanism the opposite end of the conduit I2 is partially closed by a conical valve I5 mounted on a shaft I I forming a continuation of the shaft II but of reduced diameter. The

1 ting at one end against base portion I5 of the valve I5 and at the other end against a washer I5 backed up by a nut IS on a screw-threaded and H of the shaft II. By this mechanism, material being thus forced through the opening I is incrementally packed in a plug-forming space I2= between the projecting end of the screw I2 and the conical valve I5. As the conveyor screw I0 is continuously revolved and conveys material through the opening I continuously, such material will be continuously and incrementally packed in the space It", the incremental packing being due to the fact that an amount of material less than the capacity of the conduit I2 and its screw I2 will be continuously fed through feed opening I and this lesser amount of material will be continuously added incrementally to a plug of material filling the space I2. In this way, the packing of the plug of material in the space I2 will be more dense and compact than would be possible for example with a conduit of an area similar to the entrance aperture, and experience has shown that in order to produce a satisfactory impervious plug, it is highly desirable, if not absolutely necessary, to form such plug in a conduit preferably of substantially cylindrical shape so as to enable the movement of the plug therethrough without sticking or clogging and at the same time to pack the same incrementally so as to provide for the dense packing necessary. I have also found that it is highly desirable, if not absolutely necessary, to utilize a screw mechanism which will continuously cause such an incremental packing of the material within the conduit l2.

It is also desirable, in a device of the character specified, in order to mount thereon, the valve IE, to utilize a shaft II which extends axially through the conduit l2. however, that when such a shaft is employed, there is a tendency for the liquid in the ma terial at the packing side of the plug to form a channel surrounding the said shaft, and thus to pass through the plug. In order to overcome this difllculty and to avoid formation of such a channel so that the plug within the conduit I2 will be completely impervious, I provide the shaft H with a slight gradual taper from the portion where the valve I5 is mounted thereon to the connection thereof with the screw-mounting portion ll of the screw-shaft ll.

Any suitable solvent may be employed and in the form of my invention illustrated I utilize gasoline and provide a solvent inlet-pipe I! through which I preferably force such light solvent under pressure by the pump 16.

Extraction takes place within the tank I as hereinabove indicated, and miscella passes out through the pipe l8 which communicates with the tank I through a screened elbow IS. The miscella thence passes to a distiller, not shown.

In Figs. 6 and '7, I have shown my mechanism for continuously forming a liquid impervious plug applied to an extraction unit that is adapted for use with a heavier solvent or one having specific gravity greater than that of the material, so that such material will be buoyant and will have a tendency to float and move upwardly in the liquid solvent. As illustrated, an extraction tank 20 is filled with the material through inlet 20 and floats upwardly to the top of the tank and is then moved laterally to the material outlet 20.

In the embodiment of my invention shown, I have applied at both these inlet and outlet openings 20 and MI mechanism for forming a liquidimpermeable plug embodying my invention, one of such mechanism being applied at the material inlet 20' to form such an impervious plug between the said inlet and a feed-hopper 23 while a another similar mechanism embodying my invention is applied at the material-discharge or outlet-end of said extraction unit, so that material may be discharged from the tank below the liquid level.

The plug-forming mechanism shown at the top of Fig. 6 is in all essential respects similar to the embodiment shown and described in relation to Figs. 1 to 5 except that the inclined sides of the tank and the material trough shown in Figs. 1 to 5 are inverted. Thus, the upper part of the extraction tank 20 is provided with upwardly inclined side walls 20, 20 merging into an inverted arcuate trough 24, within the curve of which is mounted a similar perforated conveyor screw ill. This conveyor screw is mounted upon a shaft ll supported on the tank at one end in a bearing 25 and rotated through pinions 24', 2 1* and shaft I have fOllIld;

24 transmitting power from any suitable source not shown. The conveyor screw H1. is, in all respects, similar to the conveyor screw I0 hereinabove described in respect to Figs. 1 to 5 and, cooperating with the inverted trough 6, conveys material to and through the material-discharge outlet 20 and into a conduit l2 cooperating with an enlarged screw 12 rotating within said conduit I2 Said conduit is of larger area' and diameter than the outlet aperture or material discharge opening 20*- and said screw 12 is of larger diameter than the conveyor screw l0. In the embodiment of my invention shown in Figs. 6 and 7 the buoyant material is incrementally packed within the conduit l2 between said screw 12 and a valve l5 mounted on a tapered shaft I I and constructed and arranged in all respects similarly to similar parts of the mechanism hereinabove described in respect to Figs. 1 to 5.

The plug-forming mechanism shown at the material-inlet in the lower end of the extraction tank shown in Fig. 6 is likewise in all respects similar to the mechanism hereinabove described in respect to Figs. 1 to 5 except that the conveyor-screw lll extends within a feed hopper 23 filled with dry material instead of being mounted within the tank l, and the conduit 2| is of larger diameter than the outlet 23' of the said feedhopper instead of being similarly larger than the outlet opening of the extraction tank I while the opposite end 2l of the conduit 2| extends through the inlet or feed opening 20 of the tank 20 within which opening it is suitably mounted. Also the conical valve l5 and adjacent parts are disposed within the tank 20 and discharge or feed material thereto. In this embodiment, the conveyor screw lo and packing screw I2 are mounted similarly to the construction shown in Figs. 1 to 5 on a shaft 26 supported at one end by a bracket 21 and at the other end by bracket 28 and rotated through pinions 29 and shaft 33 from any suitable source of power not shown.

The tank 20 may and preferably is provided with the intermingling zones (1, b formed by discs 3 and accompanying apertures 3 and scraper arms 5, and as illustrated, the tank is provided with an axial shaft 4' supported at its upper and lower ends in bearingbrackets 9, 9 and rotated through pinions 3|, 3| and shaft 32 from any suitable source of power not shown.

As the detail of construction of the conveying and incrementally packing screws and conduits and valves are all similar to that hereinabove described in relation to Figs. 1 to 5 and as the movement and operation thereof will be in all respects similar, further explanation and description will be unnecessary except to say that the screws [0 and 12 need not be perforated as they are operating to feed dry material into liquid in the tank whereas screws l0 and l2 of Figs. 6 and '7, are preferably perforated in a manner similar to the screws l0 and 12 of Figs. 1 to 5 as hereinabove specified.

In the extraction unit of Figs. 6 and 7 the material to be extracted is fed in through the feed opening 20 at the bottom of the tank 20 while heavy solvent is fed through the solvent inlet 33 from conduit 34 at the upper end of the tank 20 in counter-current to the movement of thematerial. After extraction, the miscella will pass through the outlet 35 and conduit 35 to the miscella outlet 35*. In the embodiment shown, the miscella is shown as being led upwardly through the conduit 25 until it reaches the liquid level 36 of the solvent in the conduit or pipe 34,

after which it may be conducted to a distiller not shown.

Having described my invention, I claim:

1. Apparatus for continuously forming a liquidimpervious plug for extraction units employed in the solvent extraction of oil-bearing solid materials embodying, in combination, a conduit having an inner wall provided with an entrance opening of a transverse area smaller than the transverse area of said conduit, conveyor means for continuously passing solid material through said entrance opening of said conduit, valve mechanism for partly closing the outer end of said conduit and applying pressure against movement of said material through said conduit, and a packing screw conveyor of larger capacity than said entrance opening mounted in said conduit, said packing screw conveyor having its receiving end in abutment with said inner wall of the conduit for immediately receiving, through said opening, a smaller quantity of material than its capacity and conveying said material to its delivery end, said delivery end of the packing screw conveyor being spaced from said valve mechanism to provide a packing space for continuously and incrementally packing, within said conduit, the material passing through said entrance opening to form a liquid-impervious plug moving through said conduit.

2. Apparatus for continuously forming a liquid-impervious plug for extraction units employed in the solvent extraction of oil-bearing solid materials embodying, in combination, an extraction tank, a conduit connected with said tank and having an inner wall provided with an entrance opening communicating with the interior of 'said tank, said entrance opening being of a transverse area smaller than the transverse area of the conduit, conveyor means within said tank to continuously convey solvent-impregnated solid material through said conduit-entrance opening, valve mechanism for partly closing and applying pressure at the opposite end of said conduit, a packing screw conveyor of larger capacity than said entrance opening mounted in said conduit and having passages for returning liquid to the said interior of the tank, said packing screw conveyor having its receiving end in abutment with said inner wall of the conduit for immediately receiving, through said opening, a smaller quantity of solvent-impregnated material than its capacity and conveying solid material to its delivery end while returning impregnating liquid to the tank, said delivery end of the said packing screw conveyor being spaced from said valve mechanism to provide a packing space for continuously and incrementally packing, within said conduit, the material conveyed through said entrance opening, whereby a liquid-impervious plug is formed and continuous projection and discharge of end portions of said plug is caused.

3. Apparatus for continuously forming a liquid-impervious plug for extraction units employed in the solvent extraction of oil-bearing solid materials embodying, in combination, an extraction tank, a conduit connected with said tank and having an inner wall provided with an entrance opening of a transverse area smaller than the transverse area of said conduit, said entrance opening communicating -with the interior of said tank, a single continuous conveyor mechanism for moving solid material from said tank into said conduit comprising a conveyor screw portion rotatable within said tank to continuously convey solvent impregnated solid material through said conduit-entrance opening and into said conduit, and another screw portion within said conduit of larger diameter than the conveyor screw within said tank, valve mechanism for partly closing and applying pressure at the opposite end of said passage, said two screw portions being connected together and said larger screw portion comprising a packing member provided with liquid return passages and having its receiving end in abutment with said inner wall of the conduit for immediately receiving, through said opening, a smaller quantity of solventimpregnated material than its capacity and conveying solid material to its delivery end while returning impregnating liquid to the tank, said delivery end of said packing screw conveyor being spaced from said valve mechanism to provide a packing space for continuously and incrementally packing within said conduit, the materialconveyed through said conduit-entrance opening, whereby a liquid-impervious plug is formed and continuous projection and discharge of end portions of said plug is caused.

4. Apparatus for continuously forming a liquid-impervious plug for extraction units employed in the solvent extraction of oil-bearing solid materials embodying, in combination, a cylindrical conduit having an inner wall provided with an entrance opening of a transverse area smaller than the transverse area of said conduit, means for conveying solid material through said entrance opening of the conduit, valve mechanism for partly closing and applying pressure at the opposite end of said conduit, a packing screw having liquid return passages and oi. a diameter larger than said entrance opening within said conduit having its receiving end arranged in abutment with said inner wall of the conduit for immediately receiving, through said opening, a smaller quantity of solvent-impregnated material than its capacity and conveying solid material to its delivery end while returning impregnated liquid to the tank, said delivery end of the said packing screw conveyor being spaced from said valve mechanism to provide a packing space for continuously and incrementally packing, within said conduit, the material conveyed through said opening into said conduit, ribs on the internal surface of said cylindrical passage, whereby a liquid-impervious plug is formed and continuous projection and discharge of end portions of said plug is caused.

5. Apparatus for continuously forming a liquid-impervious plug for extraction units employed in the solvent extraction of oil-bearing solid materials embodying, in combination, an extraction tank, a cylindrical conduit having a circular entrance opening of a diameter shorter than the transverse diameter of said conduit, said entrance opening communicating with the interior of said tank, a single continuous conveyor mechanism for moving solid material from said tank into said conduit comprising a conveyor-screw portion rotatable within said tank to continuously convey solid material through said entrance opening of the conduit, and another screw portion of larger diameter than said opening arranged within one end of said conduit in axial alignment with said first mentioned conveyor screw portion for continuously and incrementally packing, within said conduit, the material conveyed through said opening, a spring-pressed conical valve for partly closing and applying pressure at the opposite end of said conduit, and a shaft connecting said larger diameter screw portion and valve, said shaft being provided with a shank tapering from said valve inwardly toward said large-diameter screw portion. 6. Apparatus for continuously forming a liquid-impervious plug for extraction units employed in the solvent extraction of oil-bearing solid materials embodying, in combination, an extraction tank, a cylindrical conduit having a circular entrance opening of a diameter shorter than the transverse diameter of said conduit, said entrance opening communicating with the interior of said tank, a single continuous conveyor mechanism for moving solid material from said tank into said conduit comprising a conveyorscrew portion rotatable within said tank to continuously convey solid material through said entrance opening of the conduit, another screw portion of larger diameter than said opening arranged within one end of said conduit in axial alignment with said first mentioned conveyor screw portion for continuously and incrementally packing, within said conduit, the material conveyed through said opening, spiral ribs on the internal surface of said cylindrical passage, a spring-pressed conical valve for partly closing and applying pressure at the opposite end of said conduit, and a shaft connecting said larger diameter screw portion and valve, said shaft being provided with a shank tapering from said valve inwardly toward said large-diameter screw portion.

7. In a method for continuously forming liquid impervious plugs in extraction units, the steps which consist in forming in said unit with solid oil-bearing material and an extraction liquid a hydrostatic head, feeding from said unit with a conveyor of relatively small capacity a relatively small feed of liquid-impregnated solid material, continuously forming said eed,'in-a packing spacewithin a screw conveyor connected with said unit and having a larger capacity than the volume of said relatively small feed of said liquid-impregnated material, into a liquid impervious plug having one side open to-the atmosphere and the other side holding back said hydrostatic head, by continuously packing the inner portion; of said plug, continuously discharging the outer portion of said plug and continuously returning to said hydrostatic head the "impregnatingeliquid part of. said feed.

mCI-IELE BONOTTO. 

